to hurt the dominant opposition. Sony has a loyalty advantage. Fanboys are stupid enough to go out and buy it at any cost, just to say they have a PS3.
While you are probably right, the gamble to hurt Sony might pay off in software sales. Lets say that they lower the price by $50 and thus a new buyer says, I guess I'll get another game for $60. Assuming MS makes $10 of the game, they only lost $40 on that console. They look $50 cheaper, only take a loss of $40 and stop one more sale of a PS3. I can see them doing it, because MS is nasty like that.
you still have to think about the ramifications of that $40 loss... sell another 5 million units with that price structure and MS just lost another $200M on TOP of whatever they are already losing on each system. That one game sale means nothign to them.
And in regards to stopping the sale of a PS3, as was mentioned, they already have a nice foothold in that argument. They are $200 cheaper than the PS3 out of the gate. Kids will have a much harder time saving up for a PS3, so they may get a 360 instead. Parents will get their kids a new system... but why not save $200 by getting a 360? People like us, even if we really WANT a PS3, are likely to hold off because of the high price. I'd say MS is in a nice situation in regards to that. A price drop would make the 360 look slightly better... but IMO, there is no business sense behind the move.
I still say they will go with a bundle. Games cost next to nothing compared to systems. Even peripherals are cheap comparatively. They can throw in 2 or 3 games even, make it a really nice bundle... and they'll look a ton better than a bare $600 PS3 with no games. Plus... with a price drop, you are stuck into it for the life of they system. Short of a rebate or similar offer, you'll never be able to go back to a more expensive price after a price drop. With a bundle, you can offer it for a few months to steal Sony's thunder, and then take it off if it is hurting your bottom line.
Microsoft is a lot of things, but they aren't stupid.